U.S. patent application number 10/296567 was filed with the patent office on 2004-01-15 for method for producing document cards comprising several layers and document cards produced therewith.
Invention is credited to Fischer, Dirk, Henn, Ralf, Schumacher, Matthias.
Application Number | 20040007324 10/296567 |
Document ID | / |
Family ID | 7642984 |
Filed Date | 2004-01-15 |
United States Patent
Application |
20040007324 |
Kind Code |
A1 |
Henn, Ralf ; et al. |
January 15, 2004 |
Method for producing document cards comprising several layers and
document cards produced therewith
Abstract
The invention relates to a method for producing a multi-layer
document card, especially an identity card made of plastic,
comprising several layers. Said card comprises a card core with at
least one card core layer, a protective layer on at least one side
of said card core, and adhesive layers between the individual card
layers. The card core is printed on either on one or two sides. The
method is carried out in the following manner: The printed layers
of the card core are prepared, the protective layers are prepared,
the adhesive layers are applied to the individual protective and/or
core layers, the individual card layers are precisely positioned
one on top of the other, the card layers are joined together in a
lamination press with the aid of pressure and heat. An adhesive
system which is cross-linked under the effect of pressure and/or
heat, comprising a thermoplastic synthetic component and a
cross-linking component, is used in at least one adhesive
layer.
Inventors: |
Henn, Ralf; (Hardert,
DE) ; Fischer, Dirk; (Borchen, DE) ;
Schumacher, Matthias; (Borchen, DE) |
Correspondence
Address: |
Fulbright & Jaworski
Twenty-Ninth Floor
865 South Figueroa Street
Los Angeles
CA
90017-2571
US
|
Family ID: |
7642984 |
Appl. No.: |
10/296567 |
Filed: |
May 5, 2003 |
PCT Filed: |
April 12, 2001 |
PCT NO: |
PCT/EP01/04232 |
Current U.S.
Class: |
156/327 ;
156/182; 156/313; 283/107; 283/74; 428/195.1; 428/203 |
Current CPC
Class: |
B42D 25/45 20141001;
B42D 25/46 20141001; B42D 25/23 20141001; B42D 25/465 20141001;
B42D 25/455 20141001; Y10T 428/24802 20150115; B42D 25/47 20141001;
C08G 18/8061 20130101; B32B 2429/00 20130101; B32B 37/1207
20130101; B32B 7/12 20130101; Y10T 428/24868 20150115; B42D 25/00
20141001; B32B 2425/00 20130101; B32B 2038/0076 20130101; C08G
18/705 20130101 |
Class at
Publication: |
156/327 ; 283/74;
283/107; 428/195.1; 428/203; 156/182; 156/313 |
International
Class: |
B42D 015/00; B32B
007/14; B32B 003/10; C09J 001/00; B32B 031/00; C09J 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 20, 2000 |
DE |
100 25 093.9 |
Claims
1. Method for producing multi-layer document cards, especially a
multi-layer identity card made of plastic, comprising several
layers, with said card comprising a card core with at least one
card core layer, a protective layer on each side of said card core,
and adhesive layers between the individual card layers, and with
the card core being imprinted either on one or on two sides; the
method is carried out in the following manner: The printed layer(s)
of the card core are prepared, the protective layers are prepared,
the adhesive layers are applied to the individual protective and/or
core layers, the individual card layers are precisely positioned
one on top of the other, the card layers are joined together in a
lamination press with the aid of pressure and heat; characterized
in that, an adhesive system which is cross-linked under the effect
of pressure and/or heat, comprising a thermoplastic synthetic
component and a cross linking component, is used in at least one
adhesive layer.
2. The method according to claim 1, characterized in that the
adhesive system comprises a thermoplastic synthetic material with
double bonds and one peroxide.
3. The method according to claim 2, characterized in that the
peroxide has an activation temperature of 60.degree. C. or
above.
4. The method according to claim 2 or 3, characterized in that the
peroxide has an activation temperature ranging between 80.degree.
C. and 250.degree. C.
5. The method according to at least one of the claims 2 to 4,
characterized in that the thermoplastic synthetic material is an
unsaturated polyamide.
6. The method according to claim 5, characterized in that the
unsaturated polyamide is a condensate from polyamines and
unsaturated dimeric fatty acids.
7. The method according to claim 6, characterized in that the
unsaturated dimeric fatty acid is a dimerized linoleic acid.
8. The method according to claim 1, characterized in that the
adhesive system contains, side by side, a polyisocyanate component
and a plastic component that reacts with it and contains active
hydrogen.
9. The method according to claim 8, characterized in that the
polyisocyanate is a polyisocyanate on the basis of HDI, IPDI, TDI
or MDI.
10. The method according to claim 8 or 9, characterized in that the
polyisocyanate is present in partially cross-linked condition with
a polyamine.
11. A method according to at least one of the claims 8 to 10,
characterized in that the isocyanate groups of the polyisocyanate
are blocked.
12. The method according to claim 11, characterized in that the
polyisocyanate deblocks at 60.degree. C. or higher.
13. Method according to claims 11 or 12, characterized in that the
polyisocyanate deblocks at a temperature ranging between 80 and
250.degree. C.
14. The method according to at least one of the claims 11 to 13,
characterized in that the polyisocyanate is blocked with phenol,
E-Caprolactam, butanonoxim or malonic ester.
15. The method according to at least one of the claims 11 to 13,
characterized in that the polyisocyanate is blocked by dimerization
to form urethdion.
16. The method according to at least one of the claims 11 to 13,
characterized in that the polyisocyanate is blocked mechanically by
microencapsulation.
17. The method according to at least one of the claims 8 to 16,
characterized in that the plastic component is a polyesterpolyol,
polyetherpolyol, OH functional polyacrylate resin or polyamine.
18. Two-pack adhesive system especially for the production of
multi-layer documents, particularly identity cards of plastic
material, said system comprising of a thermoplastic hot-melt
adhesive component and a separate cross-linking component,
characterized in that the adhesive system is capable of being
cross-linked through the application of pressure and heat.
19. The adhesive system according to claim 18, characterized in
that the adhesive system comprises a thermoplastic synthetic
material with double bonds and one peroxide.
20. The adhesive system according to claim 19, characterized in
that the peroxide has an activation temperature of 60.degree. C. or
above.
21. The adhesive system according to claim 19 or 20, characterized
in that the peroxide has an activation temperature ranging between
80.degree. C. and 250.degree. C.
22. The adhesive system according to at least one of the claims 19
to 21, characterized in that the thermoplastic synthetic material
is an unsaturated polyamide.
23. The adhesive system according to claim 22, characterized in
that the unsaturated polyamide is a condensate from polyamines and
unsaturated dimeric fatty acids.
24. The adhesive system according to claim 6, characterized in that
the unsaturated dimeric fatty acid is a dimerized linoleic
acid.
25. The adhesive system according to claim 18, characterized in
that the adhesive system contains, side by side, a polyisocyanate
component and a cross-linking component that reacts with it and
contains active hydrogen.
26. The adhesive system according to claim 25, characterized in
that the polyisocyanate is a polyisocyanate on the basis of HDI,
IPDI, TDI or MDI.
27. The adhesive system according to claim 25 or 26, characterized
in that the polyisocyanate has been partially cross-linked with a
polyamine.
28. An adhesive system according to at least one of the claims 25
to 27, characterized in that the isocyanate groups of the
polyisocyanate are blocked.
29. The adhesive system according to claim 28, characterized in
that the polyisocyanate has a deblocking temperature of 60.degree.
C. or higher.
30. The adhesive system according to claim 28 or 29, characterized
in that the deblocking temperature ranges between 80 and
250.degree. C.
31. The adhesive system according to at least one of the claims 28
to 30, characterized in that the polyisocyanate is blocked with
phenol, E-Caprolactam, butanonoxim or malonic ester.
32. The adhesive system according to at least one of the claims 28
to 30, characterized in that the polyisocyanate is blocked by
dimerization to form urethdion.
33. The adhesive system according to at least one of the claims 28
to 30, characterized in that the polyisocyanate is blocked
mechanically by microencapsulation.
34. The adhesive system according to at least one of the claims 25
to 33, characterized in that the plastic component is a
polyesterpolyol, polyetherpolyol, OH functional polyacrylate resin
or polyamine.
35. Multi-layer document card, especially an identity card made of
plastic, comprising a card core with at least one card core layer,
with said card core being printed on either on one or two sides, a
protective layer on at least one side of said card core, and
adhesive layers between the individual card layers, characterized
in that said identity card being provided according to the method
specified under at least one of the claims 1 to 17.
36. Multi-layer document card, especially an identity card made of
plastic, comprising a card core with at least one card core layer,
with said card core being printed on either on one or two sides, a
protective layer on at least one side of said card core, and
adhesive layers between the individual card layers, characterized
in that at least one of the adhesive layers is produced with the
aid of an adhesive system according to at least one of the claims
18 to 34.
Description
[0001] The invention relates to a method for producing multi-layer
document cards, especially multi-layer identity cards made of
plastic, with said card comprising a card core with at least one
card core layer, a protective layer on at least one side of said
card core, and adhesive layers between the individual card layers,
and with the card core being printed on either on one or two sides;
the method comprises the following process steps: preparing the
printed layer(s) of the card core, preparing the protective layers,
applying the adhesive layers to the individual protective and/or
core layers, positioning the individual card layers precisely one
on top of the other, and joining the card layers together in a
lamination press with the aid of pressure and heat; as well as a
two-pack adhesive system and identity cards produced therewith.
[0002] Multi-layer identity cards are widely used in the form of
check and banker's cards as well as identity documents. More often
than not such cards are provided with a magnetic strip or
integrated circuit (semiconductor component, chip). Identity cards
with chip are termed chip cards or smart cards. In this manner
multi-layer identity cards with chip are frequently used to provide
authorized access to GSM mobile radio systems where the identity
card owner identifies themselves towards the mobile network
operator as authorized subscriber by inserting their identity card
(GSM card) into the mobile terminal device.
[0003] For the card layers--card core layers as well as protective
layers--various materials can be put to use: polyvinyl chloride
(PVC), polycarbonate (PC), acrylic nitrile-butadiene-styrole (ABS),
polyethylene terephthalate (PET, PETG, PETF). For identity
documents paper core layers are customarily used. The choice of
materials and the card build-up are governed by various factors.
These factors are, for example, the desired mechanical properties
of the identity card to be produced, its behavior in response to
high or low temperatures, the question whether the material can be
printed on, the question whether the card can be printed on via
laser, as well as economical and ecological necessities.
[0004] Multi-layer identity cards are produced by initially making
available the card core with imprints on one or two sides. The card
core comprises either one card core layer with imprints on one or
two sides or two card core layers of which at least one outward
facing side has been printed on. Following this, the protective
layers of the card are prepared. All layers are bonded together
with the aid of a lamination press.
[0005] To bring about an adequate bonding action between the
individual layers adhesive coats are applied as a rule. To bond the
card core layers together one of these layers is also coated with
adhesive material. For the purpose of applying the protective
layers the adhesive coating may either be put on the back of the
protective layers or on the card core layer already provided with
an imprint.
[0006] Adhesive materials that are currently in use are preferably
formulations prepared on the basis of polyurethanes, polyesters or
polyamides and/or their copolymers. In particular thermoplastic
adhesive formulations are used. A cross-linking of these
thermoplastic adhesive materials by way of subjecting them to
high-energy radiation is a known method but requires an additional
processing step and also involves a risk in that the plastic and/or
adhesive materials used for the product may undergo detrimental
changes. Attention is drawn in particular to the fact that a number
of plastic materials tend to discolor when subjected to high-energy
radiation.
[0007] The use of covalently cross-linked adhesive systems has not
been disclosed hitherto. However, especially such covalently
cross-linked adhesive material formulations are expected to enhance
the strength of the bond and, particularly, improve the temperature
resistance and resistance to solvents.
[0008] Indeed, of special interest is an improved temperature
resistance, on the one hand, to prevent the cards from
deforming/changing under the influence of heat as already
encountered with existing systems if cards placed behind the
windshield of a motor car are subjected to sunlight. But what is
more, a non-destructive delamination of the printed card and
protective layers shall also be prevented on a long-term basis to
rule out a falsification and abuse of such identity cards.
[0009] Consequently, the objective underlying the invention is to
provide a method and adhesive material system suited to enable a
durable and particularly temperature and solvent resistant bond of
the individual layers of a multi-layer document, in particular an
identity card, to be achieved.
[0010] What is to be achieved, inter alia, is an increase of the
strength of the bond between protective layer and printed-on card
core layer superior to formulations hitherto used so that a
non-destructive delamination of the bonded foils is positively
ruled out.
[0011] This objective is fulfilled by providing a method of the
type described above wherein in at least one adhesive layer an
adhesive system cross-linked under the influence of pressure and/or
heat is used that has a thermoplastic synthetic component and a
cross-linking component.
[0012] Furthermore, the invention relates to a two-pack adhesive
system which may in particular be used for the production of
multi-layer identity cards of plastic and comprises of a
thermoplastic hot-melt adhesive component and a separate
cross-linking component; such adhesive system is capable of being
cross-linked through the application of pressure and/or heat.
[0013] The invention is described below taking identity cards of
plastic as an example. However, the same applies analogously to all
multi-layer documents such as data media, identity documents, value
documents and the like, which have a core made of plastic or some
other material.
[0014] Thermoplastic adhesive systems are preferably used for the
production of cards to be used for numerous applications since they
are superior to other products as far as workability, bonding
strength and temperature resistance are concerned. Nevertheless,
such adhesive systems have certain impairments which for the main
part are due to the fact that their behavior is reversible under
the influence of temperature and solvents. According to the present
invention such impairments can be overcome.
[0015] In the light of the adhesive system the characteristics and
embodiments of the invention are described in detail hereunder for
the method and for the adhesive system.
[0016] The adhesive system to be used according to the invention
is, in particular, a thermoplastic synthetic material with double
bonds combined with a peroxide. Preferred thermoplastic synthetic
materials with double bond are polyamides, especially
polycondensates that are formed as a result of diamines reacting
with dimerized fatty acids. As initial or basic product
polyfunctional amines, such as, for example, ethylene diamine or
polyethylene amines are used as a rule that are caused to undergo a
reaction with higher dicarboxylic acids, preferably dimerized fatty
acids from linoleic acid, oleic acid or tall oil fatty acid. The
thermoplastic polyamides known by the term polyamide resins are
obtained by polycondensation. Aside from these (homo)polyamides of
a more or less clearly defined molecular structure appropriate
copolyamides of a specific characteristic profile can be built up
by varying the initial or basic products (various diamines, amino
carboxylic acids and their lactames with other dicarboxylic acids)
as well as their interrelationship. However, a prerequisite for the
usability of such polyamide resins according to the invention is
that their molecular structure still contains a C.dbd.C double
bond. Basically, all thermoplastic polyamide resins that still
contain C.dbd.C double bonds can be used for purposes in the
framework of the invention.
[0017] According to the invention it is provided that these still
existing double bonds are used for cross-linking in a radical chain
reaction. The radical starter molecules/cross-linking agents used
for this purpose consist of peroxides and act as initiators of the
radical polymerization. According to the respective processing
temperature the following organic peroxide compounds are suited,
Inter alia, as so-called radical starters:
[0018] methyl ethyl keton peroxide (.about.80.degree. C.)
[0019] dibenzoyl peroxide (.about.100.degree. C.)
[0020] di-tert-butyl peroxide (.about.150.degree. C.)
[0021] cumol hydroperoxide (.about.180.degree. C.)
[0022] tertiary butyl peroxy benzoate (.about.130.degree. C.)
[0023] tertiary butyl hydroperoxide (.about.200.degree. C.).
[0024] It is of special advantage if the processing temperature of
the hot-melt adhesive (softening temperature or lamination
temperature) corresponds to the activation temperature of the
radical starter. In this manner the lamination temperature required
for the relevant hot-melt adhesive can at the same time be utilized
for the activation of the radical starter. With a typical
processing temperature in the range of between 130 and 150.degree.
C. thermoplastic resins of double-bonding nature having a softening
temperature within this range could therefore be put to use
together with dibenzoyl peroxide, di-tert-butyl peroxide or
tertiary butyl peroxy benzoate. Adhesive systems consisting of
these components will only be activated and cross-linked when the
lamination temperature takes effect whereas at normal temperatures
they are stable and can be processed in the usual manner.
[0025] The reaction diagram showing the carbon-carbon cross-linking
of a thermoplastic resin with dibenzoyl peroxide as radical starter
is indicated below. 1
[0026] Depending on the nature of the monomers underlying the
polycondensate, the rests R and R', respectively, are, e.g.:
[0027] --(CH.sub.2).sub.n--CONH--R", n=2-9,
[0028] a dimerized linolic acid rest 2
[0029] Here the rest R" represents further chain forming units of
the polyamine resin. 3
[0030] Preferably, the activation temperature for the peroxide to
be used as prescribed by the invention is 60.degree. C. or higher.
In particular, it is in the range of between 80 and 250.degree.
C.
[0031] Useful hot-melt adhesives according to the invention,
especially those on the basis of unsaturated polyurethanes,
polyesters and polyamides, expediently have a softening point in
the range of between 80 and 250.degree. C. and a melting viscosity
at 160.degree. C. of 50,000 to 110,000 mPa.s in accordance with
ASTMD3236. Especially preferred is a softening temperature that
ranges between 100 and 160.degree. C.
[0032] In the event the thermoplastic synthetic material is an
unsaturated polyamide condensates stemming from unsaturated dimeric
fatty acids are preferred. Eligible for use as polyamides are in
particular ethylene diamine, diethylene triamine and alkylene
diamine with up to 12 C atoms. Especially preferred are condensates
obtained from unsaturated dimerized linoleic acid with one of these
polyamides that satisfy the above mentioned marginal conditions
with respect to the softening point and melting viscosity
characteristics.
[0033] The adhesive system contains, as a rule, between 1 and 10%
by weight of peroxide as radical starter, in particular 2 to 5% by
weight, each based on the unsaturated thermoplastic adhesive. For
the coating of the card layers the adhesive system is normally used
in solution, with suitable solvents being, for example, toluene and
isopropanol. The coating methods and quantities are of customary
nature and known to those skilled in the art.
[0034] A further advantage of the method and adhesive system is in
particular that the adhesive system contains the thermoplastic
synthetic material component and the cross-linking component in the
form of a mixture that is only activated when elevated temperatures
take effect.
[0035] According to another preferred embodiment of the invention
the adhesive system contains, side by side, a polyisocyanate
component and a thermoplastic resin component that reacts with it
and contains active hydrogen.
[0036] In this variant of the invention the adhesive formulation
employed utilizes the reactivity of the isocyanate component for
the cross-linking of the adhesive layer. The second resin component
has free functional groups with hydrogen atoms that are reactive
towards isocyanate functions with said atoms being available as
participants in the reaction of the isocyanate groups for the
polyaddition. These are, in particular, hydroxyl groups and amino
groups. The two components, however, do not react at room
temperature or while the adhesive is being processed but only when
a critical temperature level has been exceeded which is the case
when the identity card undergoes lamination. For this purpose the
activation and processing temperatures indicated for the adhesive
system on the basis of unsaturated thermoplastic adhesives and
peroxides shall apply.
[0037] The polyisocyanate component of the adhesive system thus
contains a polyisocyanate on the basis of hexamethylene
diisocyanate (HDI), isophorone diisocyanate (IPDI), toluylene
diisocyanate (TDI), diphenyl methane diisocyanate (MDI) or the
like. For this purpose and to achieve an appropriate optical
quality and elasticity of the adhesive bond especially aliphatic
diisocyanate compounds are preferred that exhibit only a minor
tendency towards yellowing.
[0038] The polyisocyanate may be present in the form of a monomer,
but, on principle, also as a prepolymer, that is partially
cross-linked with the aid of a customary cross-linking agent. Such
polymers are known and in any case contain at least two reactive
isocyanate groups per molecule/chain to enable the reaction to be
continued. Customary cross-linking agents for the formation of
prepolymers are glycols, polyetherols and polyesterols but also
polyamines.
[0039] To prevent a premature reaction of the adhesive system
(already at room temperature) the polyisocyanate component has been
blocked. For this purpose two methods are available as follows.
[0040] In the event a chemical blocking or capping method is
employed the NCO groups used are caused to react using customary
blocking agents which are again split off at a temperature level
higher than the deblocking temperature. Using an HBL blocking agent
the reaction takes place as shown below: 4
[0041] In this case as well the adhesive system at room temperature
represents a stable system comprising two components. By selecting
the appropriate blocking agent the blocking temperature can be
varied. Moreover, the deblocking temperature can be lowered through
the use of catalysts. The following blocking agents may be
employed:
[0042] Phenol (140 to 180.degree. C.)
[0043] .epsilon.-Caprolactam (160 to 180.degree. C.)
[0044] Butanonoxim (135 to 155.degree. C.)
[0045] Malonic ester (100 to 130.degree. C.).
[0046] The blocking process may also be brought about by a special
method, i.e. by the dimerization of isocyanate groups to form
urethdion, with such dimerization taking place catalytically
according to the following scheme. 5
[0047] During such an "internal" blocking process the isocyanate at
the same time serves as blocking agent offering the advantage that
no blocking agent will be set free during deblocking and thus
cannot impair the adhesive power of the adhesive system.
[0048] Blocking of the polyisocyanate may also be accomplished with
the aid of mechanical means, i.e. by a microencapsulation of the
isocyanate component. In any case the adhesive system is present in
the form of a suspension of two components, i.e. of the
microencapsulated isocyanate component within the cross-linking
agent that both cannot be mixed with each other. Only if a critical
temperature is exceeded will the encapsulation be reversed; the
release of the polyisocyanate which is then thoroughly mixed with
the cross-linking agent enables the cross-linking reaction to take
place.
[0049] The encapsulation of the isocyanate component can be
achieved per se by known methods, for example by a partial reaction
of the isocyanate groups with diamines or polyamines. In this case
prepolymers are produced in the form of polyurethane resins, which
envelope residual polyisocyanate in the form of microscopic
particles and isolate it from the environment.
[0050] When the microencapsulated isocyanate component is
integrated into the adhesive system a stable system comprising two
components is obtained which reacts only at temperatures above
approx. 80 to 100.degree. C. after the polyurethane has melted off
or dissolved.
[0051] As resin component and reactant for the polyisocyanates all
forms of polyols and higher molecular-weight and thermoplastic
polyamines can be employed, for example polyetherols, polyesterols,
OH functional poly(meth)acrylates and -urethane or NH.sub.2
functional polyamides. Especially suited is a number of OH
functional resins such as for example polyacrylate resins having a
molar mass ranging between 2000 and 6000 g/mol and an OH content of
between 1 and 5% by weight, saturated polyester having a molar mass
of between 500 and 6000 g/mol and an OH content between 1 and 8% by
weight and polyether having a molar mass of between 500 and 3000
g/mol and an OH content between 1 and 12% by weight.
[0052] The reaction diagram in this case is as follows: 6
[0053] According to the invention the cross-linking density may be
adjusted via the proportion of reactive groups in such a way that
the thermoplastic character of the adhesive layer disappears but
the required elasticity is maintained.
[0054] Even with this embodiment of the method and adhesive system
according to the invention the lamination temperature and
activation temperature for the adhesive system are matched to each
other in such a manner that activation takes place automatically as
soon as the lamination temperature is reached. This will then
initiate the cross-linking of the thermoplastic synthetic material
of the adhesive system.
[0055] As mentioned above, the adhesive system in this case may
also be processed in the form of a solution in, for example,
toluene; however, the liquid nature of the thermoplastic synthetic
material component may be utilized as a rule to apply the
system.
[0056] The adhesive systems according to the invention may contain
customary additives in order to influence stability and workability
or reduce the activation temperature, for example. Especially
silicate may be employed as filler material because this will
enable a thixotropic setting of the adhesive system to be achieved
which will make it easier to apply it to the card layers.
[0057] Finally, the invention relates to a multi-layer identity
card made of a synthetic material which comprises of a card core
with at least one card core layer imprinted on one or two sides,
one protective layer on each side of the card core as well as
adhesive layers between the individual card layers, with said
identity card being provided according to the above described
method or by making use of the above described adhesive system.
[0058] The use of the cross-linked adhesive system according to the
invention in particular leads to an increase of the temperature
resistance and bonding strength of objects stuck together with it.
Of material importance for such an improved property profile is
that an initially purely thermoplastic reversible adhesive system
has been transposed into a system featuring a cross-linked
structure. Adhesive systems of this kind increase the security with
a view to preventing manipulation, e.g. by a delamination of
individual protective layers in laminated identity cards.
[0059] Furthermore, the adhesive systems according to the invention
may also be used to laminate or foil-coat magnetic strips,
holograms, signature strips and other applications on cards and
identity documents. In such cases as well they are advantageously
employed with a view to providing a higher bonding strength,
temperature and solvent resistance to protect against manipulations
and abuse.
[0060] Moreover, the adhesive systems may be used in all technical
fields where a durable cross-linking of the adhesive layer will be
of benefit.
* * * * *